The global positioning system (GPS) was created by the U.S. Department of Defense. In 1983, Korean Air Lines Flight 007 was shot down by the USSR after the flight strayed into the USSR's airspace. In response, U.S. President Ronald Reagan issued a directive making GPS available for civilian use. Since President Reagan's directive was issued, portable navigation devices have become popular tools. Additionally, the number of cellular telephone users worldwide has skyrocketed. Some estimates put the number of cellular subscribers in the United States at over 275 million. An increasing number of mobile devices such as cellular telephone devices include rudimentary navigation services, in addition to traditional voice services and data services. As such, it is possible for many mobile subscribers to use some navigation features provided by a mobile device.
Unlike GPS-based navigation devices, mobile devices do not necessarily rely solely upon GPS to provide navigation services. Some mobile devices use A-GPS, location beacons, recognized network access points, and the like, to determine location and to provide location based services such as navigation. As such, mobile devices can provide navigation services in areas and locations at which a traditional GPS-based navigation device may be unusable.